The present invention relates to a negative-working, radiation-sensitive mixture containing a binder and a polymer having 1, 2, 3-thiadiazole groups.
Negative-working, radiation-sensitive mixtures have been extensively described in the literature. Despite various embodiments, the solubility of each of these radiation-sensitive mixtures in a suitable developer is diminished by a photochemically initiated reaction.
The abovementioned principle also occurs in a recording material containing unsaturated, polymerizable compounds in combination with a photoinitiator. The recording material is exposed image-wise by means of light or radiation in the absorption region of the photoinitiator and the polymerization reaction which results is, if desired, accelerated by increasing the temperature.
The unexposed, i.e., unpolymerized areas of the recording material, are then removed by means of a suitable developer. EP-A 0,053,708 is representative of such a system.
In a different variation, the photoreaction leads to the formation of crosslinkable intermediates which are then crosslinked with suitable functional groups of other components present in the radiation-sensitive mixture, e.g., a binder. Radiation-sensitive mixtures of this type contain, for example, at least bifunctional azides as the radiation-sensitive component. Some of the many possible examples are described in DE-A 1,572,067, 1,572,068, 1,572,069 and 1,572,070.
There are also systems whose hydrophilicity changes upon exposure to light radiation. Classed with these systems are mixtures containing diazonium salts in combination with suitable binders. The exposure to light cleaves off nitrogen, which drastically reduces the alkali solubility of the radiation-sensitive mixture in the image-wise exposed areas as a result of subsequent reactions. These systems are described in EP-A 0,152,819 and 0,048,876.
While the first-mentioned photopolymerizable systems offer advantages with respect to sensitivity, since a reinforcing effect occurs through the radical-induced chain mechanism, the two last-mentioned systems offer advantages in the resolution and quality of the structures which are reproduced.
Specifically, for producing structures by means of high-energy ionizing radiation (e.g., electron and X-rays), negative-working, light-sensitive mixtures based on polyacrylates and polychloromethylstyrenes are used. In these systems, a reinforcing effect is also present, although they are crosslinking systems, since the quantum yield in these cases for the crosslinking reactions is considerably greater than one.
However, the negative-working, radiation-sensitive systems described are all very limited with respect to the radiation to be selected. Thus, not only the radiation-sensitive mixtures containing components having azide groups but also those containing compounds having diazonium groups have absorption maxima in the near UV region (.about.365 nm), since the functional groups described are bound directly to aromatic systems. However, radiation-sensitive mixtures of this type require a binder as an additional component. On the other hand, polyacrylates and polychloromethylstyrenes only have low sensitivity in the UV(II) region. They are therefore extremely limited in their application range in this region.